ECG NOTES

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ECG NOTES
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Conduction System
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Heart Beat

• Graphic from Boston Scientific International.
• Start the Heart

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ECG
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ECG Parts

• P Atrial depolarization (contraction)
• QRS Ventricular depolarization (contraction
  BP systole)
• T Ventricular repolarization
• (rest BP diastole)
• U Atrial repolarization
• (rest BP diastole)

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Important Times

• 1 small square 0.04 second
• 1 large square 0.2 second
• Atrial contraction P-R interval (PRI)
• 0.1-0.2 second
• Ventricular contraction QRS complex 0.04-0.11
  second
• Always use 6 second (30 large squares) strip to
  analyze an ECG waveform

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Sinus Rhythms always have P wave followed by QRS

• Normal Sinus Rhythm (NSR) rate is
• 60-100 and rhythm is regular

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Sinus arrhythmia rate is 60-100 and rhythm is
irregular
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Sinus bradycardia rate is less than 60 and is
usually regular
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Sinus tachycardia rate is more than 100 and
less than 150 is usually regular
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Atrial Rhythms P wave and/or PRI are abnormal.
QRS may be missing after some P waves. QRS is
always normal, if it is present
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Premature Atrial Contraction (PAC)

• Rate is usually normal and may be regular except
  when the PAC occurs. Some contractions have a
  shortened PRI or the P wave may not be identified
  because it is buried in the T wave.

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Atrial tachycardia (A Tach)

• Rate is 150-250) and usually regular. PRI is
  shorter than normal and the P wave may move up on
  the T wave or be buried in it (wet T). Each P
  wave is followed by a QRS complex.

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Atrial Flutter (AF)

• Rate is 250-400. P waves are usually 0.2 seconds
  each and occur in clusters of 2, 3, or 4 (look
  like saw teeth). Each cluster is followed by a
  QRS complex at regular intervals. Because of
  this, they are classified as being AF 21, 31,
  or 41.

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Atrial fibrilliation (A-Fib)

• Atrial rate is too fast to count and individual P
  waves may be difficult to identify. Normal QRS
  complexes appear at irregular intervals. There
  will be many more P waves than QRS complexes. May
  cause blood clots to form and be sent to the
  brain, heart or lungs.

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• Atrial Fibrillation

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Ventricular Rhythms rate varies. No P wave in
front of abnormally wide QRS complexes (they will
be greater than 0.1 second). It may be difficult
to identify parts as being QRST. There will be
more QRS complexes than P waves in the strip.
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Premature Ventricular Contraction

• Rate is usually normal and may be regular except
  when PVC occurs. PVC may occur alone at regular
  intervals (bigeminy, trigeminy) or in clusters
  (salvos). If 6 or more PVCs occur in 1 minute,
  the heart is becoming very irritable and
  ventricular tachycardia can begin at any time.

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Ventricular tachycardia (V Tach)

• Rate is 150-250 and regular (looks like ric rac).
  No P waves are seen. This is a continuous PVC run.

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Ventricular fibrillation (V Fib)

• Rate is too irregular to count. Cannot identify
  any par of the waveform.

21
Asystole Straight line

• No heart activity is seen.
• Clinical death is present.
• Will become biological death if lasts longer than
  4-6 minutes.

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Pathology of MI

• Plaque builds up slowly (frequently LAD)
• Sudden blockage occurs and muscle and nerve
  tissue distal begin to malfunction and then die
• Abnormal activity and contractions
• Leads to V Fib/Asystole
• Scar tissue may form during healing and cause
  disrhythmias.

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Coronary Vessels
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Plaque
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Myocardial Infarction

• Heart Attack

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MI Treatment

• Aimed at restoring coronary blood flow
• Angioplasty and stent placement
• Coronary artery by-pass graft (CABG)
• Anticoagulants heparin and coumadin
• Aspirin (ASA) anticoagulant and
  anti-inflammatory agent

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Pathology of CHF

• Congestive heart failure
• Damaged valves or ventricular muscle
• Heart cannot completely empty
• Right failure blood backs up in legs (pitting
  edema, 1 to 4)
• Left failure blood backs up in lungs (pulmonary
  edema)
• Cardiotonic lanoxin, digoxin (not if pulse lt
  60)
• Diuretic - lasix

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CHF

• Heart Failure

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Test Your Knowledge

• Label the Parts of Your Heart
• Label Your Heart's Electrical System
• Name Your Blood Vessels
• Define Common Heart Problems